#include <stdlib.h>
#include "zbuffer.h"

#define ZCMP(z, zpix) ((z) >= (zpix))

void ZB_plot(ZBuffer* zb, ZBufferPoint* p) {
  unsigned short* pz;
  PIXEL* pp;
  int zz;

  pz = zb->zbuf + (p->y * zb->xsize + p->x);
  pp = (PIXEL*)((char*)zb->pbuf + zb->linesize * p->y + p->x * PSZB);
  zz = p->z >> ZB_POINT_Z_FRAC_BITS;
  if (ZCMP(zz, *pz)) {
#if TGL_FEATURE_RENDER_BITS == 24
    pp[0] = p->r >> 8;
    pp[1] = p->g >> 8;
    pp[2] = p->b >> 8;
#else
    *pp = RGB_TO_PIXEL(p->r, p->g, p->b);
#endif
    *pz = zz;
  }
}

#define INTERP_Z
static void ZB_line_flat_z(ZBuffer* zb, ZBufferPoint* p1, ZBufferPoint* p2, int color) {
#include "zline.h"
}

/* line with color interpolation */
#define INTERP_Z
#define INTERP_RGB
static void ZB_line_interp_z(ZBuffer* zb, ZBufferPoint* p1, ZBufferPoint* p2) {
#include "zline.h"
}

/* no Z interpolation */

static void ZB_line_flat(ZBuffer* zb, ZBufferPoint* p1, ZBufferPoint* p2, int color) {
#include "zline.h"
}

#define INTERP_RGB
static void ZB_line_interp(ZBuffer* zb, ZBufferPoint* p1, ZBufferPoint* p2) {
#include "zline.h"
}

void ZB_line_z(ZBuffer* zb, ZBufferPoint* p1, ZBufferPoint* p2) {
  int color1, color2;

  color1 = RGB_TO_PIXEL(p1->r, p1->g, p1->b);
  color2 = RGB_TO_PIXEL(p2->r, p2->g, p2->b);

  /* choose if the line should have its color interpolated or not */
  if (color1 == color2) {
    ZB_line_flat_z(zb, p1, p2, color1);
  } else {
    ZB_line_interp_z(zb, p1, p2);
  }
}

void ZB_line(ZBuffer* zb, ZBufferPoint* p1, ZBufferPoint* p2) {
  int color1, color2;

  color1 = RGB_TO_PIXEL(p1->r, p1->g, p1->b);
  color2 = RGB_TO_PIXEL(p2->r, p2->g, p2->b);

  /* choose if the line should have its color interpolated or not */
  if (color1 == color2) {
    ZB_line_flat(zb, p1, p2, color1);
  } else {
    ZB_line_interp(zb, p1, p2);
  }
}
